Search results for "flood"
showing 10 items of 256 documents
Two-Dimensional Hydraulic Modeling and Analysis of Morphological Changes in the Palancia River (Spain) During a Severe Flood Event on October 2000
2013
This paper analyzes the possibilities that mathematical models offer to reconstruct flood events, and to predict their erosional and sedimentary effects. To that end, the severe flood event of October 2000 of the Palancia River (Valencia, Spain) is assessed. The hydraulic reconstruction was performed with the software GUAD 2D, a two-dimensional mathematical simulation model for shallow water conditions. The results obtained from the mathematical model and the hydraulic-sedimentological analysis were compared with the flood-related features mapped by means of geomorphologic photo-interpretation and field observations. This comparative study illustrates that these models constitute a powerful…
A GIS-Based Model for the analysis of an urban flash flood and its hydro-geomorphic response. The Valencia event of 1957
2016
Summary Flash floods are recurrent events around the Mediterranean region. Extreme episodes activate hydro-geomorphic high-intensity processes with low frequency. In urban environments, the complexity becomes higher due to the existence of very quick-response runoff. However, immediate recovery works remove the urban marks. After a short time both the significance and magnitude of the hydro-geomorphic event become completely unrecognizable. Nevertheless, these episodes generate extensive documentation which is testimony of the processes in almost real time. It is necessary to exploit this source typology in order to draw flood sketches when events far in time may lack a sufficiently rich da…
Using post-flood surveys and geomorphologic mapping to evaluate hydrological and hydraulic models: The flash flood of the Girona River (Spain) in 2007
2016
This paper analyzes the Girona River (Spain) flash flood, occurred on the 12th of October 2007, combining hydrological and hydraulic modeling with geomorphologic mapping and post-flood survey information. This research aims to reproduce the flood event in order to understand and decipher the flood processes and dynamics on a system of prograding alluvial fans. The hydrological model TETIS was used to characterize the shape and dimension of the October 2007 Girona River hydrograph. Subsequently, the flood event was reproduced using the free surface flow module of the model RiverFlow2D. The combination of hydrological and hydraulic models was evaluated using post-flood surveys defining maximu…
A copula-based approach for assessing flood protection overtopping associated with a seasonal flood forecast in Niamey, West Africa
2016
Flood is one of the most important natural disasters that cause huge loss of life and properties every year around the world. Moreover, the International Federation of the Red Cross and Red Crescent Societies pointed out that floods were by far the greatest cause of homelessness. In West Africa, many countries are damaged from flooding almost every season. Thus, this study aimed to set a seasonal flood forecast model and carried out an evaluation of the level of risk associated with each seasonal forecast. HEC-RAS (Hydrologic Engineering Centers River Analysis System) was used to develop a hydro-dynamical model of Niger river on a 160km reach (80km upstream to 80kmdownstream of Niamey), the…
Historical morphogenesis of the Turia River coastal flood plain in the Mediterranean littoral of Spain
2011
Abstract The cross-referencing of sedimentological, stratigraphic, geoarchaeological and radiocarbon data enables us to establish the geomorphologic evolution of the Late Holocene coastal flood plain of the Turia River. The Holocene marine transgression formed a coastal barrier lagoon environment in the coastal plain. During the Late Holocene, increased sediments supplied to the low reach of the river promoted: (a): the progradation of deltaic coastal sandy ridges on the coastline and (b): the aggradation of the floodplain on top of the sedimentary sequence. Four phases are clearly recognised in the geoarchaeological record of the flood plain. (1): High magnitude flooding events (2800 BP to…
Human induced soil erosion and gully system development in the Late Holocene and future perspectives on landscape evolution: The Myjava Hill Land, Sl…
2013
In humid climate zones, like Central Europe, past soil erosion and gullying are strongly connected with agricultural expansion, and extreme soil erosion events often play an important role in land abandonment. This paper provides a case study to demonstrate the interaction between land use, soil erosion, floodplain development, and land use changes in a 0-order catchment in the Babikovce catchment, Myjava Hill Land, situated in western Slovakia. Sedimentological, pedological, geoarchaeological and historical data indicate two main periods of intensive hillslope erosion and gullying since the High Middle Ages. In particular, a few extreme precipitation events (or rapid snowmelts) caused inte…
Rainfall thresholds derivation for warning pluvial flooding risk in urbanised areas
2016
Aim of this work is the development of an operational tool for pluvial flooding warning in an urban area based on off-line rainfall thresholds derived by coupling a rainfall–runoff modelling and a hydraulic routing. The critical conditions considered for issue flood warnings were not only based on the water stage, but also on the extension of the flooded area. Further, a risk assessment framework for quantifying the reliability of the rainfall thresholds has been included; rainfall thresholds used in pluvial flooding warning should be influenced by the uncertainties in the rainfall characteristics (i.e. rainfall duration, depth and storm pattern). This risk assessment framework incorporates…
Finite-Element Modeling of Floodplain Flow
2000
A new methodology for a robust solution of the diffusive shallow water equations is proposed. The methodology splits the unknowns of the momentum and continuity equations into one kinematic and one parabolic component. The kinematic component is solved using the slope of the water level surface computed in the previous time-step and a zero-order approximation of the water head inside the mass-balance area around each node of the mesh. The parabolic component is found by applying a standard finite-element Galerkin procedure, where the source terms can be computed from the solution of the previous kinematic problem. A simple 1D case, with a known analytical solution, is used to test the accur…
Flood pattern changes in the rivers of the Baltic countries
2015
Estimation of both the frequency and variation of spring floods is a key issue for the assessment and management of flood risks. Changes in river floods in Estonia, Latvia and Lithuania have been investigated in few national studies. However, there are no studies of the changes of flood patterns by using a common methodology for the rivers of this region. In this study flood pattern changes in the rivers of the Baltic countries were estimated applying trend and frequency analysis for the periods of 1922–2010, 1922–1960, 1961–2010 and 1991–2010, i.e. for the whole spring flood data sets, periods before and after 1960 (this year was considered as the beginning of the remarkable climate change…
Hydrogeomorphological analysis and modelling for a comprehensive understanding of flash-flood damage processes: the 9 October 2018 event in northeast…
2020
31 Pags.- 12 Figs.- 5 Tabls. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.